The present invention relates generally to molded articles. In one aspect, the invention comprises molded articles bearing a surface image while in another aspect, the invention relates to molded articles bearing a lenticular image. In yet another aspect, the invention pertains to a method of making molded articles bearing an image, and more particularly, a lenticular image.
Molded articles and their methods of manufacture are well known in the art. Typically, these articles are molded from any one of a number of common plastics, e.g., ABS, acrylic, polystyrene, polyethylene, polypropylene, PET, nylon, polycarbonate, and the like, and these articles are molded into any one of a host of different sizes and shapes, e.g., telephone, compact disc and cosmetic cases, cups, bottles, promotional items, automobile and appliance parts, etc. These products are molded or shaped by any one of a number of different processes, e.g., injection molding, resin transfer molding, blow molding, pressure molding, and the like. Such parts can be complex, that is, comprising more than one injection molded part. For example, a cosmetic case can include an opaque portion and a separately or even simultaneously molded clear portion.
The aesthetic quality of a molded plastic part is, of course, dependent in large part upon its ultimate use. For those products that are used in applications in which their use is not visible to an end user, e.g., fasteners, plugs, etc., the aesthetics of the product are of little, if any, importance. For those products that are used in applications in which their use is visible to an end user, or in which their appearance is important to their sale, e.g., promotional items, automobile and appliance facie, cups, bottles, bottle caps/enclosures, snowboards or wake boards, skis (e.g., water, snow), cameras, computer cases (e.g., laptop cases), cell phone (or other electronic) cases, cosmetic cases, collectibles, signs, magnets, coasters, display posters, menu boards, postcards, business cards, and packaging on boxes, the aesthetics of the product are important.
One way to improve the look of a product is to incorporate into it bright color schemes and fancy or even glitzy decor so as to attract and keep a viewer""s attention. The application of a lenticular image is one form of such a decor. As here used, a xe2x80x9clenticular imagexe2x80x9d means a segmented image comprising two or more component images, the segments interlaced in any conventional manner, and mapped (i.e., aligned) to a lenticular lens. In general, lenticular imaging is known, commercially available and described in U.S. Pat. Nos. 5,113,213; 5,266,995; 5,488,451; 5,617,178; 5,847,808; 5,896,230 and 5,967,032 (all of which are incorporated herein by reference), and U.S. application Ser. No. 09/536246.
The incorporation of a decorative surface feature into a molded product is known, e.g., U.S. Pat. Nos. 5,514,427; 5,985,198; 5,972,279; 5,968,444; 5,951,939; 4,906,315; 4,668,558; 4,582,885; 4,576,850 and Re. 36,457 (all of which are incorporated herein by reference).
In general, molded parts are used in a variety of applications and lenticular images provide an attractive and eye-catching way to improve the overall aesthetic appeal of an object to the viewer. Current technology provides for injection molding of colored plastics and plastics which can incorporate such decorative features as, for instance, a xe2x80x9csparkle.xe2x80x9d
A method for manufacturing a molded article having a decorative surface layer comprising a lenticular image is of interest to the injection molding industry as well as consumers of molded products in general in that it can provide a product that is simply more beautiful or attractive. On another level, the product can be used to communicate a message (inanimate though it may be) via the decorative lenticular image. A method that can promote the integrity of the lenticular image and the lenticular image""s adhesion to the molded article while also protecting the optical properties achieved by the lenticular lens surface is desirable.
According to this invention, a molded article bearing a lenticular image is prepared by an in-mold method comprising the steps of:
A. providing a mold in which to form a molded article;
B. inserting a lenticular image into the mold;
C. introducing a molten plastic into the mold to form the molded article with the lenticular image attached to a surface of the molded article; and
D. removing the molded article with the attached lenticular image from the mold.
In one embodiment of this invention, the molded article is formed by an in-mold method of injection molding in which the lenticular image is placed on the surface of one or both halves of the mold and held in place with a vacuum assist, the molten plastic injected into the mold to create the molded article with the lenticular image attached to the surface of the article, and the mold subsequently opened and the finished article removed.
In another embodiment of this invention, the lenticular image bears a coating over the segmented, interlaced and mapped image that protects the integrity of the image from distortion and/or degradation that would otherwise result from the heat and pressure of the molten plastic during the molding process. In other embodiments of this invention, the temperature and pressure of the molten plastic is selected and/or controlled, and/or the gate placement is selected, such that the integrity of the lenticular image remains undistorted without the need for a protective coating.